Abstract: A device is disclosed. The device includes a. at least one radiation emitting element configured for emitting a modulated thermal radiation as a result of its temperature; where the radiation emitting element includes at least one incandescent lamp; and b. at least one electronic circuit configured for applying a periodic time-dependent voltage to the radiation emitting element, wherein where the electronic circuit is configured for controlling one or more of an amplitude, a duty cycle and a frequency of the periodic time-dependent voltage, where a temperature of the radiation emitting element and a frequency of the modulated thermal radiation depend on the applied periodic time-dependent voltage controlled by the electronic circuit.